The slavery debate revolved around several critical issues. Unlike the industrialized North, the economy of the South was largely agricultural and depended on enslaved labor. Southerners felt that the states, rather than the federal government, should have the right to decide whether residents could own slaves or not. People in the North and the South worried about whether the Western territories would enter the Union as slave or free states, since that could influence the balance of power in Congress. Most importantly, within this economic and political context, Congress grappled with the morality of slavery. Was slavery morally acceptable, an evil to be tolerated or a reprehensible institution that must be abolished? Some opposed the mere spread of slavery but not the institution itself.

March 3, 1820: Missouri Compromise

The Missouri Compromise was the first major legislative compromise passed to settle the slavery issue by drawing a line between slave and free territory. Speaker of the House Henry Clay promoted the deal, which admitted Maine to the Union as a free state and Missouri as a slave state. The act prohibited slavery in territories and new states above the 36º 30´ latitude line, with the exception of Missouri, and maintained a balance in the Senate between slave and free states.

In the late 1830s, Congress received more than 130,000 petitions from citizens demanding the abolition of slavery in Washington, D.C., and other federally-controlled territories. In 1836, the House passed a resolution to its rules of procedure which banned the discussion of these petitions. The so-called “gag rule” was reinforced in 1839, 1841 and 1843 as part of the rules readopted by the House with each new Congress. However, Representative and former President John Quincy Adams, who considered the gag rule a violation of his constituents’ First Amendment rights, used creative tactics to stir debate on the floor. In 1844, the House repealed the gag rule on a motion made by Adams.

After war with Mexico added new territories to the Southwest, the issue of slavery’s expansion gained renewed urgency. Senator Henry Clay of Kentucky championed a series of compromise measures in an effort to heal the growing rift between the northern and southern states. Senator Daniel Webster of Massachusetts spoke eloquently in defense of the compromise, while Senator John Calhoun of South Carolina opposed the plan. With the guidance of Stephen Douglas of Illinois, Congress eventually passed revised versions of Clay’s proposed bills, known collectively as the Compromise of 1850. The Compromise admitted California to the Union as a free state, allowed the territories of New Mexico and Utah to decide the slavery issue for themselves, and settled a Texas boundary and debt issue. While it abolished slave trade in the District of Columbia, it strengthened the existing Fugitive Slave Law by requiring free states to return escaped slaves to their owners.

Introduced by Illinois Senator Stephen Douglas, the Kansas-Nebraska Act granted the residents of these territories “popular sovereignty,” or the power to decide whether to allow slavery. The act repealed part of the Missouri Compromise that prohibited slavery above the 36° 30´ latitude. It sparked violence in Kansas when pro-slavery and anti-slavery settlers fought for control of the territory. Much to Douglas’s dismay, the conflict fueled tensions between the North and South and brought the nation closer to civil war.

The violence erupting in Kansas as a result of the Kansas-Nebraska Act spilled over into the halls of Congress. In 1856, South Carolina Representative Preston Brooks beat Massachusetts Senator Charles Sumner with a cane because he condemned the pro-slavery views of Brooks’s relative, Senator Andrew Butler. Two years later in a late night House session, a brawl involving more than 50 representatives broke out over the expansion of slavery into Western territories. The fight ended in comedy when one member snatched an opponent’s wig, exclaiming “I’ve scalped him!” Despite the levity, the brawl was seen as a foreboding sign of conflicts to come.